Can anyone explain how this code INSERTS data into a database? - android

Can someone explain to me how this code works and how I am inserting this data into the database? I Java two Java files. The first piece of code is located in the first Java file and the second is located in the second Java file. Why am I passing the following parameters ImageID, currentDay, v.getID. Then when I call the insertNewRoutine function it is using the parameters int activityResourceID, String day and int slot? Confused about why it's using that?Thanks in advance!
boolean routineInserted = myDb.insertNewRoutine(ImageID, currentDay, v.getId());
if (routineInserted == true) {
Toast.makeText(MondayRoutineEdit.this, "Activity Inserted", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(MondayRoutineEdit.this, "Activity Not Inserted", Toast.LENGTH_LONG).show();
}
public boolean insertNewRoutine(int activityResourceID, String day, int slot)
{
SQLiteDatabase db = this.getWritableDatabase();
db.execSQL("DELETE FROM " + RoutineTable + " WHERE DayID ='" + day + "' AND SlotID =" + slot);
ContentValues contentValues = new ContentValues();
contentValues.put(RoutineColumn2, day);
contentValues.put(RoutineColumn3, activityResourceID);
contentValues.put(RoutineColumn4, slot);
long result = db.insert(RoutineTable, null, contentValues);
if (result == -1)
return false;
else
return true;
}

ContentValues contentValues = new ContentValues();
contentValues.put(RoutineColumn2, day);
contentValues.put(RoutineColumn3, activityResourceID);
contentValues.put(RoutineColumn4, slot);
long result = db.insert(RoutineTable, null, contentValues);
You are population the content values (they are going to be inserted as VALUES in sql) with function paramaters.
This method call is responsible for insertion.
SQLiteDatabase.class exposes methods to manage a SQLite database.
Reference to the official android documentation
https://developer.android.com/reference/android/database/sqlite/SQLiteDatabase.html#insert(java.lang.String,%20java.lang.String,%20android.content.ContentValues)

Related

Insert if not exists: SQLite

I want to insert data if that headline doesn't exist yet in the database.
This is the error I'm getting for the written query:
near "with": syntax error (code 1): , while compiling: SELECT * FROM movie WHERE headline=Albert Collen
Code:
public boolean Insert(Item item) {
SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
Cursor cursor = sqLiteDatabase.rawQuery("SELECT * FROM " + TABLE + " WHERE headline=" + item.getName() , null);
if (cursor.moveToFirst()) {
} else {
contentValues.put("name", item.getName());
long result = sqLiteDatabase.insert(TABLE, null, contentValues);
if (result == -1) {
return false;
} else {
return true;
}
}
cursor.close();
sqLiteDatabase.close();
return true;
}
You should use query parameters
rawQuery("SELECT * FROM movie WHERE headline = ?", new String[] {"Albert Collen"});
to avoid having to escape quotes and other chars.
First of all, result query is wrong. All the string constants are to be quoted, like this
SELECT * FROM movie WHERE headline='Albert Collen';
So, try to compose query like this, perhaps it will help
Cursor cursor = sqLiteDatabase.rawQuery("SELECT * FROM " + TABLE + " WHERE headline='" + item.getName() + "'" , null);
But concatenating a query is not a good idea because it makes at least SQL-injections possible.
For example, it can cause problems when item.getName() contains following line "'; drop table movies;"
Better option would be using bind query variables. Unfortunately, I'm not familiar with how to use java-android with sqlite, so it is better for you to check how to use such a queries in android

Get a specific value from a specific column from specific row?

i have a table names "highscore"
In the table there is:
id (int) ,
name (string) ,
win(int) ,
draw(int),
loss(int).
I want to make a query that i can get the specific value win from the row , only the integer.. how can i do that? i want to handle sql injection to.
I have a method that update the win, but i need to get the win, increment the value with 1 and then update. My update method is this and it works:
public void updateWin(String playerName, int win) {
SQLiteDatabase db = this.getReadableDatabase();
ContentValues values = new ContentValues();
values.put(Constants.KEY_WIN, win);
db.update(Constants.TABLE_NAME, values, Constants.KEY_PLAYER_NAME + "= ?", new String[]{playerName});
db.close();
}
Anyone can help me please? thanx
Option 1 - Increment according to arithmetic calculation within SQL
You could base the this on the SQL (assuming the table is mytable001 and the player's name is FRED) :-
UPDATE mytable001 SET win = win +1 WHERE playername = 'FRED';
This would do away with the need to query the playername to get the current number of wins as it directly increments the value.
However, this cannot be done via the convenience update method nor a rawQuery you have utilise execSQL.
So the following could be used :-
public boolean incrementWin(String playerName) {
SQLiteDatabase db = this.getWritableDatabase();
String esc_playername = DatabaseUtils.sqlEscapeString(playerName);
String qrysql = "UPDATE " +
Constants.TABLE_NAME +
" SET " +
Constants.KEY_WIN + " = " +
Constants.KEY_WIN + " + 1" +
" WHERE " +
Constants.KEY_PLAYER_NAME + "=" + esc_playername;
db.execSQL(qrysql);
long changes = DatabaseUtils.longForQuery(db,"SELECT changes()",null);
db.close();
return changes > 0;
}
Note if the update couldn't be/ wasn't performed then it would return false.
The use of sqlEscapeString, will escape the playername and I believe offer some protection against SQL Injection.
Option 2 - Retrieve current value, calculate new, update using new :-
public boolean incWin(String playername) {
SQLiteDatabase db = this.getWritableDatabase();
String whereclause = Constants.KEY_PLAYER_NAME + "=?";
String[] wherargs = new String[]{playername};
int win = -1; // default to not update
Cursor csr = db.query(
Constants.TABLE_NAME,
null,
whereclause,
wherargs,
null,
null,
null
);
if (csr.moveToFirst()) {
win = csr.getInt(csr.getColumnIndex(Constants.KEY_WIN)) + 1;
}
csr.close();
if (win < 1) {
db.close();
return false;
}
ContentValues cv = new ContentValues();
cv.put(Constants.KEY_WIN,win);
if (db.update(Constants.TABLE_NAME,cv,whereclause,wherargs) > 0) {
db.close();
return true;
}
db.close();
return false;
}
Note if the update couldn't be/ wasn't performed then it would return false.

Record is not getting update in database

I have saved data in database. I am trying to update data.
But record is not getting update.
If I debug the update function it shows the values i have entered. But when I retrieve the data it dose not show updated values.
What's wrong?
update function in helper class
public int updateEvent(EventData event) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_TITLE,event.getTitle());
values.put(KEY_FROM_DATE,event.getFromDate());
values.put(KEY_TO_DATE,event.getToDate());
values.put(KEY_DAY_OF_WEEK,event.getDayOfWeek());
values.put(KEY_LOCATION,event.getLocation());
values.put(KEY_NOTIFICATION_TIME,event.getNotificationTime());
// updating row
return db.update(TABLE, values, KEY_ID + " = ?",
new String[] { String.valueOf(event.getId()) });
}
updating in activity:
if (editMode) {
eventData.setTitle(title.getText().toString());
eventData.setFromDate(showFromTime.getText().toString());
eventData.setToDate(showToTime.getText().toString());
eventData.setDayOfWeek(selectDay.getText().toString());
eventData.setLocation(mAutocompleteView.getText().toString());
eventData.setNotificationTime(notifyTime.getText().toString());
db.updateEvent(eventData);
}
else {
db.addEvent(new EventData(eventTitle, startTime, endTime, dayOfWeek, location, notificationTime));
}
setResult(RESULT_OK, i);
finish();
}
Thank you..

Saving and retrieving accented characters to mysql database

I'm having some trouble saving a string with an accent to my database and retrieving it.
This is my function that saves a new location to the database. It gets 'myId' and 'location' and inserts them. The println there shows the item as I expect, with the accent. The example I'm using is Mazzarrà.
public long createLocationRecord(String location, int myId) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_OWMID, myId);
values.put(KEY_NAME, location);
System.out.println("newItem in DB = "+location);
long callSQL = db.insertWithOnConflict(TABLE_LOCATION, null, values, SQLiteDatabase.CONFLICT_IGNORE);
if(callSQL==-1)
db.update(TABLE_LOCATION, values, KEY_OWMID + '=' + owmId, null);
return callSQL;
}
This is my function to retrieve all location items. The println here prints out Mezzarra, without the accented à. Am I missing something? Do I need to make a change to my database? It's just a regular Android SQLite DB that I'm opening via SQLiteBrowser.
public ArrayList<String> getLocationList() {
ArrayList<String> list = new ArrayList<String>();
SQLiteDatabase db = this.getWritableDatabase();
String selectQuery = "SELECT * "
+ "FROM " + TABLE_LOCATION
+ " ORDER BY _id ASC";
Cursor c = db.rawQuery(selectQuery, null);
if (c != null)
c.moveToFirst();
if (c.moveToFirst()) {
do {
System.out.println("newItem GETTING FROM DB = "+c.getString(c.getColumnIndex(KEY_NAME)));
list.add(c.getString(c.getColumnIndex(KEY_NAME)));
} while (c.moveToNext());
}
c.close();
return list;
}
Thanks for any help anyone can provide.

Updating a single column is creating sqlite syntax error

I'm not sure what I'm doing wrong, but I'm trying to update a single integer value in a column of a table to 1 from 0. When creating the database, I set all values of the column to zero using:
for (int i = 0; i < setups.length; i++) {
ContentValues values = new ContentValues();
values.put(JokeDbContract.TblJoke.COLUMN_NAME_SETUP, setups[i]);
values.put(JokeDbContract.TblJoke.COLUMN_NAME_PUNCHLINE, punchlines[i]);
values.put(JokeDbContract.TblJoke.COLUMN_NAME_USED, 0);
db.insert(JokeDbContract.TblJoke.TABLE_NAME, null, values);
}
Then, in the actual activity, I'm doing:
private void findNewJoke() {
JokeDb jokeDb = JokeDb.getInstance(this);
SQLiteDatabase theDb = jokeDb.getDB();
String selection = JokeDbContract.TblJoke.COLUMN_NAME_USED + "=" + 0;
// Query database for a joke that has not been used, update the fields
// theJoke and thePunchline appropriately
String[] columns = {JokeDbContract.TblJoke._ID,
JokeDbContract.TblJoke.COLUMN_NAME_PUNCHLINE,
JokeDbContract.TblJoke.COLUMN_NAME_SETUP,
JokeDbContract.TblJoke.COLUMN_NAME_USED};
Cursor c = theDb.query(JokeDbContract.TblJoke.TABLE_NAME, columns, selection,
null, null, null, null);
if (c.moveToFirst() == false) {
Toast.makeText(this, R.string.error_retrieving_joke, Toast.LENGTH_LONG).show();
Log.e(getString(R.string.app_name),"No jokes retreived from DB in JokeActivity.findNewJoke()!");
}
else {
ContentValues values = new ContentValues();
theSetup = c.getString(c.getColumnIndexOrThrow(JokeDbContract.TblJoke.COLUMN_NAME_SETUP));
thePunchline = c.getString(c.getColumnIndexOrThrow(JokeDbContract.TblJoke.COLUMN_NAME_PUNCHLINE));
String updateSelection = JokeDbContract.TblJoke.COLUMN_NAME_SETUP + "=" + theSetup;
values.put(JokeDbContract.TblJoke.COLUMN_NAME_USED, 1);
theDb.update(JokeDbContract.TblJoke.TABLE_NAME, values, updateSelection, null);
}
}
I'm getting an error on the update:
java.lang.RuntimeException: .... while compiling: UPDATE jokes SET used=?
WHERE setup=Why do programmers always mix up Halloween and Christmas?
It seems as though I'm not getting an actual value set for the used column. What the program ultimately does is cycle through jokes where used=0, then sets used to 1 when it has been viewed. So the query only pulls those jokes that aren't used yet. I have a feeling I'm missing something simple, one can hope.
I think you are having problems with quotation marks.
Example:
String updateSelection = JokeDbContract.TblJoke.COLUMN_NAME_SETUP + "=\"" + theSetup + "\"";
However, the recommended way to do this, would be:
theDb.update(JokeDbContract.TblJoke.TABLE_NAME, values, JokeDbContract.TblJoke.COLUMN_NAME_SETUP + " = ?", new String[] { theSetup });
It is better to use field = ?, because this helps sqlite cache queries (I believe).

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